There are many applications for fluid pressure transducers. The transducer is particularly useful in automobiles for measuring and indicating the pressure of lubricating oil in an internal combustion engine. It is desirable to utilize a simple yet reliable transducer which transforms linear movements into rotary movements. Linear movements are typically produced by the effects of pressurized fluid on the mid portion of a flexible diaphragm. Desired rotary motion is particularly useful for moving electrical contacts or the like across a resistance pattern or grid formed on a resistance board. Thus, the transducer must transform the linear movement to rotary movement. Resultantly, the transducer produces an electrical indication or signal which is proportional to the movement of the diaphragm caused by the effects of fluid pressure.
An early pressure indicator or transducer is disclosed in U.S. Pat. No. 1,171,480 to Troll. In the Troll patent, a member attached to a diaphragm moves linearly and its movements are transformed to rotary movement by means of a rather complex lever and gear arrangement.
Another early pressure transducer is disclosed in U.S. Pat. No. 2,877,327 to Hastings. The Hastings device utilizes a movable diaphragm responsive to the effects of fluid pressures. The diaphragm includes a central assembly which is linearly movable with the diaphragm. The central assembly defines an axial directed aperture. A elongated member or pin which has a spiral channel formed therein moves in the aperture. Rotary movement is produced by means of a follower which extends into the spiral channel. Likewise, U.S. Pat. No. 4,086,557 to Padgitt discloses a transducer utilizing a member with a sprial channel which is interactive with a stationary structure.
Another relevant patent which is known to applicant is U.S. Pat. No. 2,943,302. None of the aforementioned patents utilized or disclose the transducer structure of the subject device which is specifically described and claimed hereinafter.